Many technologies for allowing emergency driving for hundreds of kilometers even when a pneumatic tire goes flat while a vehicle is running have been proposed based on market demands. Among these many proposals, technologies which were proposed in the Japanese Patent Laid-Open Publications No. 10-297226 and No. 2001-519279 enable run-flat running by attaching a core to a rim within a hollow part of a pneumatic tire mounted on the rim and thus supporting the tire with the core when the tire goes flat.
The aforementioned run-flat core (support body) includes an annular shell and elastic rings. The annular shell has an open-leg structure with the outer peripheral side serving as a support surface and with the inner peripheral side formed into open legs. The elastic rings are attached to the two legs of the run-flat core. Thus, the run-flat core is supported on the rim via the elastic rings. This run-flat core can be used as it is without making any special modifications to existing wheels/rims. Accordingly, the run-flat core has an advantage in that the run-flat core may be acceptable to the market without causing any confusion there.
In the case of the tire/wheel assembly (wheel) having the aforementioned structure, however, a tire bead is sometimes demounted from a rim when the tire goes flat and run-flat running is performed. Thus, further run-flat running may become impossible. For this reason, while it is the most important required characteristic for the run-flat core (support body) to have a function of supporting the weight of the vehicle body during the run-flat running, it is also an important required characteristic to have an excellent function of preventing the tire bead from being demounted in terms of improvement in the run-flat durability.